This invention generally relates to computer screen displays, and more particularly to a method for effectuating the presentation of multiple overlapping images on displays commonly used in computer systems, data processing systems and electronically controlled machines, such as compressors, for example.
Modern graphics processors are capable of simultaneously executing, or essentially simultaneously executing, a plurality of separate graphics routines or programs, which may be dependent or independent. Typically, each of these graphics routines "assumes" that it may utilize an entire computer display area available to it, and outputs pixel data, i.e. image data, accordingly. Such techniques for simultaneously displaying a portion of each of the images produced by such separate graphics routines on a single screen are referred to as "windowing" techniques.
Windowing systems are a widely available and accepted means of presenting video information to a computer or equipment operator. Windowing permits the placement of multiple, overlapped pages on a single computer display or computer screen.
The human mind is capable of detecting the placement of a new page over currently displayed pages and directing its attention to the newly visible page. Proper placement of the page will keep important information in the field of view of the user for easy reference. Each page acts as an information grouping device which helps remind the user of importance and relationship of various bits of the data. This method of displaying multiple windows of information has a wide range of applications from customer information kiosks to operator interface panels on virtually any piece of complicated machinery.
Currently, systems capable of partially overlaying pages of information require significant and costly amounts of CPU power and memory storage to achieve acceptable performance. These systems also require high speed parallel datalink connections to the host processor. Attempts have been made by various display designers to migrate this functionality to low cost embedded microcontroller based electronics. When the speed and memory burdens are placed on these low cost microcontrollers, the visual update performance seen by the operator is often unacceptable. To increase the update speed, available systems place severe limitations on the placement of information. More specifically, text fonts are often limited in size and placement on the screen. Ultimately, this lowers the quality of the information presented and the delight of the user with the product.
Another severe limitation imposed by these low cost systems is that when a page is partially or fully overlaid upon page, the obscured page contents cannot be modified until the page is fully revealed. This places an undue restriction on the host processor when the processor updates information across all pages. The net result is that more cost and complexity are required of the host system to overcome this problem.
The foregoing illustrate limitations known to exist in present methods for visually multiplexing video information on a computer display, or windowing video information. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.